Rapid identification of female Culexmosquito species using Expert System in the South East Asian region

Rapid identification of mosquito (vector) species is critical for vector control and disease management. Pictorial keys of mosquito species are currently used for the identification of new mosquito species. However, this approach is not very effective. Here, we describe the use of an ID3 algorithm (part of artificial intelligence) for the rapid identification of the South East Asian female Culex mosquito species.

Availability     

Solution structure and backbone dynamics of Calsensin, an invertebrate neuronal calcium-binding protein

Calsensin is an EF-hand calcium-binding protein expressed by a subset of peripheral sensory neurons that fasciculate into a single tract in the leech central nervous system. Calsensin is a 9-kD protein with two EF-hand calcium-binding motifs. Using multidimensional NMR spectroscopy we have determined the solution structure and backbone dynamics of calcium-bound Calsensin. Calsensin consists of four helices forming a unicornate-type four-helix bundle. The residues in the third helix undergo slow conformational exchange indicating that the motion of this helix is associated with calciumbinding. The backbone dynamics of the protein as measured by (15)N relaxation rates and heteronuclear NOEs correlate well with the three-dimensional structure. Furthermore, comparison of the structure of Calsensin with other members of the EF-hand calcium-binding protein family provides insight into plausible mechanisms of calcium and target protein binding.     

Genome wide survey of G protein-coupled receptors in <Emphasis Type="Italic">Tetraodon nigroviridis</Emphasis>

Background  

The G-protein-coupled receptors (GPCRs) constitute one of the largest and most ancient superfamilies of membrane proteins. They play a central role in physiological processes affecting almost all aspects of the life cycle of an organism. Availability of the complete sets of putative members of a family from diverse species provides the basis for cross genome comparative studies.     

Severe hypertriglyceridemia in human APOC1 transgenic mice is caused by apoC-I-induced inhibition of LPL

Studies in humans and mice have shown that increased expression of apolipoprotein C-I (apoC-I) results in combined hyperlipidemia with a more pronounced effect on triglycerides (TGs) compared with total cholesterol (TC). The aim of this study was to elucidate the main reason for this effect using human apoC-I-expressing (APOC1) mice. Moderate plasma human apoC-I levels (i.e., 4-fold higher than human levels) caused a 12-fold increase in TG, along with a 2-fold increase in TC, mainly confined to VLDL. Cross-breeding of APOC1 mice on an apoE-deficient background resulted in a marked 55-fold increase in TG, confirming that the apoC-I-induced hyperlipidemia cannot merely be attributed to blockade of apoE-recognizing hepatic lipoprotein receptors. The plasma half-life of [3H]TG-VLDL-mimicking particles was 2-fold increased in APOC1 mice, suggesting that apoC-I reduces the lipolytic conversion of VLDL. Although total postheparin plasma LPL activity was not lower in APOC1 mice compared with controls, apoC-I was able to dose-dependently inhibit the LPL-mediated lipolysis of [3H]TG-VLDL-mimicking particles in vitro with a 60% efficiency compared with the main endogenous LPL inhibitor apoC-III. Finally, purified apoC-I impaired the clearance of [3H]TG-VLDL-mimicking particles independent of apoE-mediated hepatic uptake in lactoferrin-treated mice. Therefore, we conclude that apoC-I is a potent inhibitor of LPL-mediated TG-lipolysis.     

Functional significance of phytochemical lures to dacine fruit flies (Diptera: Tephritidae): an ecological and evolutionary synthesis

While lures of plant origin are vital tools in dacine (Diptera: Tephritidae) pest management, the ecological and evolutionary significance of this lure response remains enigmatic. Two hypotheses (the ancestral host hypothesis and sexual selection by female choice) have been invoked to explain the functional significance of these chemicals to dacine fruit flies. These hypotheses are often treated as alternatives to one another and evidence favouring one is used to reject the other. This review highlights that these two hypotheses are not logical alternatives to each other as the ancestral host hypothesis attempts to explain the ultimate function of the response of Dacinae to these plant-derived parapheromones while the sexual selection hypothesis provides a proximate explanation for lure response. Research on lure response, dacine mating behaviour, functional significance of lures, plant phylogeny and biochemistry and dacine pheromone chemistry are used to evaluate the evidence in relation to both these hypotheses. Some of the key findings are that there is evidence both in support of and against these two hypotheses. Response of fruit flies to related phenyl propanoids to those commonly used as lures in pest management and distribution of phenyl propanoids attractive to dacines among plant orders strongly support the ancestral host hypothesis. Evidence from pheromone chemistry, dacine mating behaviour and the functional significance of lures both support and contradict the sexual selection hypothesis. Lures appear to have different proximate functions in different dacine species. Considerably greater research is needed to clarify the functional role of phytochemical lures to dacine fruit flies. The two prevalent hypotheses should be investigated independently. Specific research on dacine phylogeny and distribution of lures in plants in relation to ecological roles played by adult dacines is required to elucidate the ultimate roles of the chemicals. Exploration of female response to lures and the behavioural consequences of dacine response to these chemicals to both the insect and plant may shed light on the proximate functions of these chemicals.     

Acanthocheilonema viteae: octopamine and its physiological role

Octopamine acts as an important neurotransmitter and neuromodulator in arthropods, mollusks, and nematodes. In mammals, however, no definite function for this amine has yet been described. By virtue of this difference in the neurophysiological requirement of the mammalian host and nematodes, octopamine offers good opportunity for exploring this area deeply with a view to identify a unique target for filarial chemotherapy. Results of the present study indicated that Acanthocheilonema viteae, the rodent filarial parasite, utilized tyrosine as a precursor for producing octopamine and some other biogenic amines. Octopamine exhibited specific saturable binding with the membrane prepared from the anterior portion of the filariid. This amine induced concentration dependent increase in the membrane potential which possibly caused tonic paralysis of the filariid. The rate of micro filarial release by the female worms also declined in the presence of this amine. The study thus provided preliminary evidences for the presence of an octopamine neurotransmitter system and also about some of the roles it plays in A. viteae.     

Concanavalin A induced activity change in yeast PM-bound NADH-HCF(III) oxidoreductase

The activity of plasma membrane bound redox enzyme, NADH-HCF(III) oxidoreductase, in wild and mutant strains of the yeast Saccharomyces cerevisiae is modulated by Con A in a dose-dependent manner. The solubilized activity is enhanced at lower concentration and inhibited at higher concentration of Con A. The enzyme in mutant strain is more sensitive to inhibition. The activation of enzyme by Con A is suppressed in the presence of either alpha-methyl-D-mannoside or 2-deoxy-D-glucose, indicating the glycoproteic nature of enzyme as well as the resulting conformational change due to interaction with Con A as the factor for modulated activities. This was supported by recording the decrease in K(m) value of enzyme with respect to substrate NADH in the presence of lower concentration of Con A. The purified enzyme was more sensitive to lectin stimulation and, on the basis of comparative stimulatory effects of Con A and PSA on activity, it is likely that mannosyl moiety in enzyme is involved in binding the lectins to cause enzymic activation.     

In vivo light-induced and basal phospholipase C activity in Drosophila photoreceptors measured with genetically targeted phosphatidylinositol 4,5-bisphosphate-sensitive ion channels (Kir2.1)

The phosphatidylinositol 4,5-bisphosphate (PIP(2))-sensitive inward rectifier channel Kir2.1 was expressed in Drosophila photoreceptors and used to monitor in vivo PIP(2) levels. Since the wild-type (WT) Kir2.1 channel appeared to be saturated by the prevailing PIP(2) concentration, we made a single amino acid substitution (R228Q), which reduced the effective affinity for PIP(2) and yielded channels generating currents proportional to the PIP(2) levels relevant for phototransduction. To isolate Kir2.1 currents, recordings were made from mutants lacking both classes of light-sensitive transient receptor potential channels (TRP and TRPL). Light resulted in the effective depletion of PIP(2) by phospholipase C (PLC) in approximately three or four microvilli per absorbed photon at rates exceeding approximately 150% of total microvillar phosphoinositides per second. PIP(2) was resynthesized with a half-time of approximately 50 s. When PIP(2) resynthesis was prevented by depriving the cell of ATP, the Kir current spontaneously decayed at maximal rates representing a loss of approximately 40% loss of total PIP(2) per minute. This loss was attributed primarily to basal PLC activity, because it was greatly decreased in norpA mutants lacking PLC. We tried to confirm this by using the PLC inhibitor U73122; however, this was found to act as a novel inhibitor of the Kir2.1 channel. PIP(2) levels were reduced approximately 5-fold in the diacylglycerol kinase mutant (rdgA), but basal PLC activity was still pronounced, consistent with the suggestion that raised diacylglycerol levels are responsible for the constitutive TRP channel activity characteristic of this mutant.     

Hypoxia augments TNF-alpha-mediated endothelin-1 release and cell proliferation in human optic nerve head astrocytes

The effect of hypoxia (24 h) on TNF-alpha-mediated release of endothelin-1 (ET-1) from human optic nerve head astrocytes (hONAs) and TNF-alpha- and ET-1-induced hONA proliferation was determined. ET-1 synthesis and release was quantitated using ELISA while TNF-alpha (10 nM)- and ET-1 (100 nM)-mediated hONA proliferation was assessed by CellTiter 96 aqueous one-solution cell proliferation assay, respectively. hONAs appeared to be more rounded with fewer processes following 24 h hypoxia compared to thodr seen in normoxia. Hypoxia enhanced TNF-alpha-mediated ET-1 synthesis and release (by 5-fold) and also significantly increased TNF-alpha- and ET-1-mediated hONA proliferation. PD142893 (1 microM), an ET(A/B) receptor antagonist, blocked ET-1-mediated hONA proliferation both under normoxia and hypoxia, while doing so only under normoxia following TNF-alpha treatment. Also, U0126 (10 microM; an upstream ERK1/2 inhibitor) completely blocked agonist-induced hONA proliferation in normoxia and partially blocked the same in hypoxia. These results demonstrate for the first time that hONAs secrete ET-1 and that TNF-alpha and hypoxia can regulate its levels. Moreover, hypoxia augments the proliferative responses of hONAs to TNF-alpha and ET-1. These agonist-mediated effects following hypoxia could contribute to astroglial activation as seen in glaucomatous optic nerve heads.